Virtual reality computer applications seek to mimic the sensory experience associated with moving through three dimensional space using only a two dimensional display device. The process requires that displayed images be updated in response to the location or position of a viewer in a defined virtual space. Significant data processing capabilities are required to determine the appropriate displayed images, and large data storage capabilities are necessary to store the images for each potential view.
Although sometimes entirely fanciful, in many applications the displayed images are in whole or in part taken from real world scenes. This is common in applications in which the objective is education. For example, the viewer could be shown scenes from a Roman piazza in order to provide an understanding of day-to-day life in the city. Marketing or advertising applications also draw from this use, showing potential customers the marketed goods in an intended or showroom environment.
Panoramic images provide the continuous scenic backdrop in these applications. Usually these images extend continuously, entirely through 360.degree.. Available software allows discrete images to be converted into the continuous panorama. The process involves rotating a common chemical-film camera around its optical center or nodal point. During the rotation, a series of overlapping photographs are taken. Rotation about the optical center ensures that perspective does not change from photograph to photograph. Thus, common portions of the panorama in successive photographs should perfectly match-up. U.S. patent application No. 08/577,292, filed on Dec. 22, 1995 by the present inventor, which is incorporated herein in its entirety by this reference, discloses a "Panoramic Indexing Camera Mount" that facilitates the photography process.
Once taken, the photographs are developed and digitized, then scanned into a computer. There, the stitching software aligns successive photographs and removes any visible seams, thus creating a continuous panoramic image.
Foreground images in virtual reality applications are constructed by a different but related process. Whereas the panorama is represented by a sphere or ring of inwardly displayed images that surround the viewer's virtual space location, foreground images are represented by a sphere of outwardly directed images of objects. The viewer may move around the objects within the virtual space and virtually manipulate those objects.